Originally, television programming was provided solely by over-the-air broadcast. The most widely received over-the-air transmissions were and continue to be in the very high frequency (VHF) band and only to a much more limited extent in the ultra high frequency (UHF) band of the RF spectrum. In recent decades, however, the delivery of television programming into the home increasingly has been delivered via CATV (cable) service. CATV transmission offered considerably higher bandwidth than was available over-the-air, while the quality of its transmission--for those equipped with the necessary coaxial cable for receiving the analog signal, and the hardware required for descrambling it--has been generally better than analog airwave transmission, which is subject to a variety of forms of signal interference.
The high bandwidth and transmitted signal quality of CATV transmission relative to over-the-air broadcasting has led to CATV being a dominant force in the market for multiple channel programming. That CATV coaxial delivery systems in principle provide sufficient bandwidth to permit two way communication with subscribers has fueled speculation that CATV may provide an early venue for the provision of interactive television services. CATV service, however, is inherently limited by the extent of its geographic penetration. CATV service is simply unavailable in locations that cable providers have chosen not to serve. Even where CATV service is available, installation of the coaxial cable is disruptive as well as expensive.
The provision of interactive programming content has become a major goal of the converging television, entertainment, programming, telecommunications, on line and computing industries. Telecommunications companies, for example, have invested significant resources in developing "video dialtone," in which programming services would be provided by way of the telephone system. Although this approach shows enormous potential and the ability to revolutionize both the telecommunications and television industries, it presents certain non-trivial technological and economic problems. The provision of video dialtone services to the home may turn on the installation of optical fiber and/or coaxial cable in place of existing twisted pair telephone connections, which presents a highly expensive and time consuming proposition that is not expected to be implemented for some time.
Aside from efforts to move to what has become known as high-definition television (HDTV), and to provide such HDTV services over the air, comparatively little attention has been paid recently to enhancing television programming services that are delivered over the airwaves. A possible reason for the comparative lack of effort may be that the perceived need to support interactivity would seem to militate against a video delivery system that uses as its transport medium one that apparently lacks a return path. The available choices for delivery of television programming, meanwhile, have continued to grow into such areas as "wireless cable" and direct broadcast satellite, tending to draw attention even further away from over-the-air broadcasting.
Another factor barring or at least complicating any attempt to provide enhanced television service over-the-air is imposed by existing federal communications regulations, set forth in Title 47 of the United States Code of Federal Regulations. These regulations establish a framework for the delivery of programming over-the-air that is as rigid as it is highly detailed, and that, short of legislation, is subject to modification only by the Federal Communications Commission, and then only within the mechanism provided by the Administrative Procedures Act, 5 U.S.C. .sctn..sctn.551-559, .sctn..sctn.701-706, .sctn.1305, .sctn.3105, .sctn.3344, .sctn.5372, .sctn.7521.
Still another obstacle to the provision of an alternative means for providing programming services on a large scale, such as by over-the-air broadcast, has to do with equipping intended recipients of the programming services with the means to receive and view the programming. Aside from the direct expense associated with providing a new device, viewers may harbor concerns about the compatibility of a new in-home device with any existing premises equipment, in which a viewer may have made a sizable investment. Even if a device were to be provided gratis by a service provider, for example, subscribers may be somewhat reluctant to commit to a particular system if it were not compatible with existing delivery systems purely for reasons having to do with such things as clutter and the consumption of available space. Nevertheless, the apparent demand not only for traditional television programming, but also for such services as home shopping, video games, data services such as electronic catalogs, stock market quotations, sports scores, and electronic newspapers, as well as interactive services and video on demand (VoD) or near video on demand (NVoD) continues to grow. This consumer demand, coupled with an increased demand by marketing organizations for demographic and consumer preference information for use in their characterizing and targeting the increasingly segmented consumer populace faced with a growing number of viewing alternatives makes clear that any alternative means for delivering programming must have a return path for enabling viewer interaction.